Apparatus for operating a burner fired shaft furnace



March 19, 1968 TAUBMANN ETAL. 3,373,981

APPARATUS FOR OPERATING A BURNER FIRED SHAFT FURNACE Filed May 26, 1965 2 Sheets-Sheet .1

Hcrro Toubmcmn Hubert Boderke INVENTORS ATTORNEYS March 1968 H. TAUBMANN ETAL 3,373,931

APPARATUS FOR OPERATING A BURNER FIRED SHAFT FURNACE Filed May 26, 1965 2 Sheets-Sheet 2 Horro Toubmonn Hubert Boderke mvsm-rons ATTORNEYS V Patented Mar. 19, 1968 3,373,981 APPARATUS FOR OPERATING A BURNER FIRED SHAFT FURNACE Harro Taubmann, Niederhochstadt, Taunus, and Hubert Boderke, Hemkenrode uber Braunschweig, Germany, assignors to Didier-Werke A.G., Wiesbaden, Germany Filed May 26, 1965, Ser. No. 459,071 Claims priority, application Germany, May 29, 1964, W 36,875 2 Claims. (Cl. 263-29) ABSTRACT OF THE DISCLOSURE The quantity of fuel required for the heat treatment of the material is subdivided differentially or uniformly to the individual burners so that the combustion in the burners of the individual burner planes or levels takes place differentially or uniformly stoichiometrically, substoichiometrically or super-stoic-hiometrically and the quantity of cool air is measured or dosed. In this way, the heat distribution in the furnace can always be adapted to the particular heat treatment to be carried out. When the burner is operated sub-stoichiometrically, the present invention employs stage burners provided with two combustion chambers and interposed guide or conduit means with the first combustion chamber located at the inlet end of the second combustion chamber and at substantially right angles thereto. Such a construction of the burners makes it possible to realize a relatively strongly reduced combustion without difficulties. Honeycomb-like nozzle blocks may be arranged in the outlet openings discharging into the furnace shaft in order to improve the penetration effect of the outfiowing gases through the loose material being treated and such blocks may, of course, also be built into burners which do not operate according to the twostage principle.

The present invention relates essentially to the distribution and apportionment of the fuel to the burners of a shaft furnace, to the dosing of the cooling air and to the detailed construction of the burners, especially when the burners are disposed in two superposed planes.

An object of the invention is, depending upon the heat treatment method to be carried out and the type of material to be heat treated, that the quantity of fuel required for the heat treatment of the material be subdivided differentially or uniformly to the individual burners, that the combustion in the burners of the individual burner planes or levels take place differentially or uniformly stoichiometrically, sub-stoichiometrically or superstoichiometrically, and that the quantity of cool air be measured or dosed. In this way, the heat distribution in the furnace can always be adapted to the particular heat treatment to be carried out and which is therefore of enhanced effect.

If the furnace is intended for a method wherein the burner is operated sub-stoichiometrically, the present invention employs stage burners provided with two combustion chambers and interposed guide or conduit means with the first combustion chamber located at the inlet end of the second combustion chamber and at substantial- :ly right angles thereto. Such a construction of the burners makes it possible to realize a relatively strongly reduced combustion Without difiiculties. Honeycomb-like nozzle blocks may be arranged in the outlet openings discharging into the furnace shaft in order to improve the penetration effect of the outflowing gases through the loose material being treated and such blocks may, of course, also be built into burners which do not operate according to the two-stage principle.

A further object of the present invention is to improve the operation of a shaft furnace for the heat treatment of loose material as described in our application Ser. No. 303,622 filed Aug. 21, 1963, entitled, A Burner Fired Shaft Furnace and Process for Operating the Same, now abandoned. In said application, the furnace is provided with burners located in the outer wall and which is operated by the blowing in of air under pressure, it being possible to withdraw gas from the top of the furnace and to reintroduce the same into the lower part of the furnace. The furnace is provided with pressure burners which are distributed about the periphery of the furnace in one plane and which selectively produce completely burned or still burnable gas, with combustion chambers which open into the furnace interior, and are provided with outlet nozzles directed horizontally or substantially horizontally toward the furnace center, and are also provided with connections for furnace waste gases and fresh air. The above application also sets forth proposals with regard to the oxygen-fuel ratios and with regard to the burners, as well as with respect to the velocities at which the fuel gases should leave the burners and as to the arrangement of the burners in the furnace shaft wall.

A preferred form of the invention is disclosed in the drawings in which:

FIG. 1 is a partial longitudinal section taken through a shaft furnace equipped according to the present invention.

FIG. 2 is a sectional view taken along section line 2-2 of FIGURE 1, on an enlarged scale.

FIG. 3 is a sectional view taken along section line 33 of FIGURE 2, on an enlarged scale.

FIGS. 4 and 5 are sectional views taken along section lines 4-4 and 5-5 of FIGURE 3 respectively.

FIG. 6 is an elevational view of a honeycomb nozzle block, and I FIG. 7 is a diagrammatic View showing the direction of burning in the present invention.

The furnace wall 1 of the shaft furnace encloses the shaft 2 and in the wall 1 there are arranged a plurality of burners 55 in two planes 56 and 57 extending transversely of the furnace with the shaft cross-section of each burner plane 56 and 57 being widened.

As shown in FIG. 2, the burners consist of a combustion chamber 58 discharging at one end into the furnace and at the other end there is a small pre-combustion chamber 59. The two combustion chambers 58 and 59 are disposed at right angles to one another. A guide means 60 is provided between the combustion chambers. The smaller primary combustion chamber 59 has an air connection 61 and a fuel connection 62, while the larger secondary combustion chamber 58 is provided only with a fuel connection 63.

The guide means 60 as shown particularly in FIGURES 3, 4 and 5 constitutes a first tubular portion at the outlet end of the combustion chamber 59 as shown in FIGURE 4 and which then gradually is converted into the rectangular cross-section as shown in FIGURE 5. From there it extends so as to encircle spirally the combustionchamber 58 at the inlet end thereof.

The honeycomb-like nozzle blocks are shown at 74 which can be inserted at the outlet end 76 of the burners. Such a block as shown in FIG. 6 is provided with the apertures 75.

The operation of the furnace, for example in the calcining of lime, is as follows:

A small portion of the fuel is burned in the smaller combustion chamber 59 with an excess of air, after which the resultant combustion gases pass through the guiding means 60 into the larger secondary combustion chamber 58, into which the major part of the fuel is sprayed which is gasified by the hot combustion gases from the first combustion chamber 59. The thus-produced hot oil gases enter into the furnace at a velocity which makes possible penetration of the bulk material as far as the furnace shaft axis or center 70. The oil gases from the lower burner plane 57 with burners 71 come into contact with cooling air ascending through the shaft 2 from the lower end thereof and are preheated by the material being treated, and burn at a temperature of 1000 to 1100 C. with excess of air, the amount of which is controlled by the supply of cool air fed to the furnace and which amounts to about 0.75 to 0.8 Nm. /kg. of introduced lime. The resultant combustion gases, which have an oxygen content of about 12 to 15%, flow to the upper burner level 56 with the burners 58, while treating the bulk material en route, and at such upper level mix with the oil gases coming from the burners at this level and which, because of oxygen deficiency, burn gently and slowly so that superheating of the material is excluded.

It is thought that the invention and its advantages will be understood from the foregoing description and it is apparent that various changes may be made in the process, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing its material advantages, the form hereinbefore described and illustrated in the drawings being merely a preferred embodiment thereof.

We claim:

1. Heating device for a burner heated blast furnace serving for the heat treatment of bulk material, driven under pressure by forcing undergrate blast into the same and by heating gases manufactured by pressure burners, whereby fresh air may be added to the controllable constructed burners for the selective production of burned out or still burnable gases, being a mixture of furnace gases and intake air or undergrate blast air prewarmed in the furnace and withdrawn below the burner, comprising a vertical shaft furnace, burners with two series-connected combustion chambers located at the side of said furnace, fuel supply connections for said burner combustion chambers independent from another, guide means connecting said combustion chambers arranged between them guiding the stream of gas manufactured in the first chamber into the second chamber.

2. A burner as claimed in claim 1 wherein the first combustion chamber in said series connected chambers is connected to the front end of the second chamber at a right angle thereto.

References Cited UNITED STATES PATENTS 513,945 6/1894 Koneman 26329 1,841,463 1/1932 Barber et al. 158--28 1,197,985 4/1940 [Priest 263-29 2,282,551 5/1942 Yates 15899 X 2,670,946 3/1954 Royster 26329 3,204,936 9/1965 Beckenbach 26329 3,275,062 9/1966 Williams 15899 FOREIGN PATENTS 1,244,302 9/1960 France.

FREDERICK L. MATTESON, JR., Primary Examiner.

J. I. CAMBY, Assistant Examiner. 

